Method of manufacturing skin-carrying internal-mold expansion molded body of synthetic resin and metal mold used for the same method

ABSTRACT

This invention relates to a method for producing cellular molded article in mold pattern of synthetic resin having surface skin which is used, for example, as an automobile interior trim material or the like and a mold pattern for producing thereof. This invention aims to provide a method for producing cellular molded article of synthetic resin having surface skin which has good production efficiency and which comprises that cellular molded article of synthetic resin obtained by cellular molding of expanded beads in which poor melt bonding does not occur and thermoplastic resin skin material united with this cellular molded article of synthetic resin which has excellent appearance without residing beads pattern on its surface, and a mold used for producing thereof. In so-called simultaneous united molding, at least the part of one mold part ( 5 ) on which thermoplastic resin skin material ( 3 ) is set is made of gas permeable metal mold, gas permeable ceramic mold or gas permeable electron casted mold ( 5   d ) having fine gas permeable holes of not more than  100  μm of diameter on the whole surface ( 5   a ) and at least during steam heating and before expanding expanded beads ( 8 ), one mold part ( 5 ) on which thermoplastic resin skin material ( 3 ) is set is made to be the upper part, and the other mold part ( 6 ) is made to be the lower part.

TECHNICAL FIELD

This invention relates to a method for producing cellular molded articleof synthetic resin with a surface skin which is used, for example, as anautomobile interior trim material or the like and a mold pattern usedfor producing the above-mentioned article.

BACKGROUND OF THE INVENTION

As for the conventional method for producing cellular molded article ofsynthetic resin with surface skin of this kind, for example, (a)so-called simultaneous molding in once is known, in which thermoplasticresin skin material is set in any one of two mold parts, and afterclamping the mold parts, expanded beads are charged in the moldingchamber, and then expanded additionally for melt bonded together bysteam heating, along with making melted bonding with the saidthermoplastic resin skin material. In this method when the said two moldparts can be opened and clamped toward vertical direction, the said onemold part has to be the lower part to make setting of the saidthermoplastic resin skin material easy.

(b) Moreover, in this simultaneous united molding, as shown in FIG. 28,it is common that the surface 5 a of the said one mold part 5 issmoothed, and that the surface 3 a of the said thermoplastic resin skinmaterial 3 is made a mat processing with a prescribed roughness andperformed to form fine and uniform unevenness 19. In this case, whenafter charging expanded beads 8 in the said molding chamber 7 andcellular molding these beads 8 by steam heating, the prescribed range Dof the surface 3 a of the said thermoplastic resin skin material 3 ispressed by the surface 5 a of the said one mold 5 harder than the otherrange E by expanding force F of the said expanded beads 8 from thebackside 3 b.

Here, since the said thermoplastic resin skin material 3 is softened bysteam heating, as shown in FIG. 29, the fine unevenness 19 d which iseven finer than the fine unevenness 19 formed in advance by matprocessing is formed in the said range D which is pressed harder asabove-mentioned. Also, the said the other range E is pressed against thesurface 5 a of the said one mold part 5 by the expanding force which issmaller than that pressing the range D. Therefore, the fine unevenness19 e which is about as fine as or a little finer than the fineunevenness 19 formed in advance by the said mat processing is formed inthe other range E. However, the fine unevenness 19 d in the said range Dis finer as a result of being pressed harder against the surface 5 a ofthe said one mold part 5, the range D appears as circular so-calledbeads pattern when looked over. This is disadvantageous as itdeteriorates the appearance of the obtained cellular molded article ofsynthetic resin having surface skin 51.

(c) As the example of conventional method to solve such problem, themethod in which, as shown in FIG. 30, laminated sheet 23 which comprisesof thermoplastic resin sheet 53 whose surface 53 a is formed to the fineunevenness 19 by mat processing and the thermoplastic resin extrudedfoam sheet 54 which is attached to the backside 53 b of thethermoplastic resin sheet 53 is used as the said thermoplastic resinskin material 3, and the sheet 23 is set as the said thermoplastic resinsheet 53 surface will come in contact with the said one mold part 5 andthe said thermoplastic resin extruded foam sheet 54 surface will come incontact with the said expanded beads 8, and other processes are the sameas the above-mentioned is known.

In this method, when the said thermoplastic resin extruded foam sheet 54is pressed from its backside 54 b by expanding force F of the saidexpanded beads 8 at the cellular molding process of the said expandedbeads 8, this thermoplastic resin extruded foam sheet 54 functions asso-called cushioning material. Therefore, it is hard for the pressingforce F to work on the surface 53 a of the said thermoplastic resin 53,consequently, the above-mentioned beads pattern does not appear.

(d) In addition to the above-mentioned simultaneous united molding, forexample, the so-called afterward attached molding, in which cellularmolded article of synthetic resin 2 and thermoplastic resin skinmaterial 3 are set between two mold parts, and when clamping the moldparts and pressurizing them, these cellular molded article of syntheticresin 2 and thermoplastic resin skin material 3 are united by heatand/or adhesives is known.

In FIG. 31, the case when the said cellular molded article of syntheticresin 2 and thermoplastic resin skin material 3 are melt bonded andunited by heat is shown. In this case, as the above-mentioned, it iscommon that the surface 15 a of the one mold part 15 which will come incontact with the said thermoplastic resin skin material 3 is smoothedand that mat processing of a prescribed unevenness is more or lessuniformly performed to form the fine unevenness 19 on the surface 3 a ofthe said thermoplastic resin skin material 3. On the other hand, it isnot common that the surface 2 a of the said cellular molded article ofsynthetic resin 2 is smoothed. Also the case of uniting cellular moldedarticle of synthetic resin 2 with thermoplastic resin skin material 3 byadhesive existing between them without heat, or the case of uniting byboth heat and adhesive is in similar conditions as above-mentioned.

However, in the conventional example of above-mentioned (a), since theexpanded beads are expanded by the said steam heating, drain (moisture)may remain in the said molding chamber during this steam heating processand before expanding process of the said expanded beads. Therefore, thedisadvantage is that this remaining drain causes poor melt bonding ofthe expanded beads in the cellular molded article of synthetic resinobtained by cellular molding process of the said expanded beads.

In the conventional example of above-mentioned (c), the disadvantage isthat, since the said thermoplastic resin extruded foam sheet 54 has tobe separately produced by foamed extrusion process, and stuck to thesaid thermoplastic resin sheet 53 beforehand, the production process iscomplicated and the production efficiency is poor.

Also, in the conventional example of above-mentioned (d), since thesurface 2 a of the said cellular molding articles of synthetic resin 2is not smooth, as shown in FIG. 31, the prescribed range D of thesurface 3 a of the said thermoplastic skin material 3 is pressed fromthe backside 3 b against the surface 15 a of the said one mold part 15harder than the other range E by pressurizing force G when melt bondingand uniting this cellular molded article of synthetic resin 2 withthermoplastic resin skin material 3 are operated.

Therefore, as is the case of simultaneous united molding ofabove-mentioned (b), the said range D appears as circular so-calledbeads pattern when looked over, and it is disadvantageous as itdeteriorates the appearance of the obtained cellular molded article ofsynthetic resin having surface skin 51. Also, when cellular moldedarticle of synthetic resin 2 and thermoplastic resin skin material 3 areunited by both heat and adhesive, similar beads pattern is observed.Moreover, when they are united by adhesive without heat, the similarbeads pattern is observed, and it is disadvantageous as above-mentioned.

This invention has been accomplished in consideration of above-mentioneddisadvantages, and aims to provide a method for producing cellularmolded article of synthetic resin having surface skin which comprises ofcellular molded article of synthetic resin obtained by cellular moldingof expanded beads in which poor melt bonding does not occur andthermoplastic resin skin material united with this cellular moldedarticle which has excellent appearance without beads pattern on itssurface, and which has good production efficiency, and a mold used forproducing thereof.

DISCLOSURE OF THE INVENTION

An essential feature residing in a method for producing cellular moldedarticle of synthetic resin having surface skin of this invention is thatin a method for producing cellular molded article of synthetic resinhaving surface skin in which thermoplastic resin skin material formed inthis molding chamber is set on one of two mold parts which comprises themolding chamber and after clamping the parts, expanded beads are chargedin this molding chamber, then expanded and melt bonded together by steamheating along with being melt bonded and united with the saidthermoplastic resin skin material, at least the part for setting thesaid thermoplastic resin skin material of the said one mold part is madeof gas permeable metal mold or gas permeable ceramic mold or gaspermeable electron casted mold having fine gas permeable hole of notmore than 100 μm in diameter on the whole surface and also the said onepart is made to be the upper mold part and the other part is made to bethe lower mold part at least during the said steam heating and beforethe expanding of the said expanded beads. Accordingly, by vacuum pumpingof the inside of the molding chamber through vapor holes or the like setin said the other part, remaining drain in the said molding chamber canbe easily removed through the lower vapor holes or the like by utilizinggravity rather than going against it. Therefore, this drain can besurely removed, and advantage is that drain remains non or little in thesaid molding chamber. Since a thermoplastic resin skin material ismolded in the said molding chamber and set on the said one mold,advantage is also that a process molding the said thermoplastic resinskin material in advance in other molding chamber or the like can beskipped. Moreover, since at least the part for setting the said plasticresin skin material of the said one mold part is made of gas permeablemetal mold, gas permeable ceramic mold or gas permeable electron castedmold having fine gas permeable holes of not more than 100 μm in diameteron the whole surface, in the case of setting the said thermoplasticresin skin material on the said one mold by vaccum forming, permeabilityof air or gas between this gas permeable electron casted mold or thelike and the said thermoplastic resin skin material can be improvedmore. Also it is advantageous that the said thermoplastic resin skinmaterial is attached more firmly on the surface of one mold part andmarks of the said gas permeable holes is not left on the surface of thesaid thermoplastic resin skin material because diameter of the said gaspermeable holes is very fine which is not more than 100 μm.

An essential feature residing in a method for producing a cellularmolded article of synthetic resin having a surface skin in whichthermoplastic resin skin material is set on one of two mold parts whichcomprises molding chamber and after clamping mold parts, the expandedbeads are charged in this molding chamber and expanded and melt bondedtogether by steam heating along with being melt bonded and united withthe said thermoplastic resin skin material, fine unevenness of 5 to 150μm in amplitude and 30 to 600 μm in wavelength of surface roughnesswaveshape measured by the surface roughness measuring instrument isformed in advance, when melting the said expanded beads together alongwith melting and uniting these expanded beads with the saidthermoplastic resin skin material, by printing the said fine unevennessto the surface of the said thermoplastic resin skin material to make thesurface roughness of thermoplastic resin skin material of a prescribedrange which is pressed harder on the surface of one mold part byexpanding force of the said expanded beads and the surface roughness ofthe other range to become about the same, the surface roughness of thisthermoplastic resin skin material is kept nearly uniform. Accordingly,in so-called simultaneous united molding, by printing the fine roughnessof the said one mold part with expanding force of the expanded beads,roughness of the fine unevenness formed on the surface of the saidthermoplastic resin skin materials respectively can be surely made to beapproximately the same. Therefore, the appearance of the article can beimproved more efficiently, and advantage of this invention is that acellular molded article of synthetic resin having surface skin andexcellent appearance without residing previous beads pattern can beproduced.

An essential feature residing in a method for producing a cellularmolded article of synthetic resin having a surface skin in whichthermoplastic resin is set on one of two mold parts which comprises themolding chamber and after clamping mold parts, expanded beads arecharged in this molding chamber and expanded and melt bonded together bysteam heating along with being melted and united with the saidthermoplastic resin skin material, the unevenness printing itemmaterials are attached to the surface of the said one part in advance,and when melt bonding the said expanded beads together along with meltbonding and uniting these expanded beads with the said thermoplasticresin skin material, by printing the fine unevenness formed on thesurface of the said unevenness printing item material having 5 to 150 μmin amplitude, 30 to 600 μm in wavelength of surface roughness waveshapemeasured by the surface roughness measuring instrument to make thesurface roughness of thermoplastic resin skin material of a prescribedrange which is pressed harder on the surface of the unevenness printingitem material by expanding force of the expanded beads and the surfaceroughness of the other range to be about the same degree to the surfaceof the said thermoplastic resin skin material, the surface roughness ofthis thermoplastic resin skin material is approximately kept constant.Therefore, in so-called simultaneous united molding, even when theunevenness printing item material is attached, by printing the fineunevenness of this unevenness printing item material with expandingforce of expanded beads, the fine unevenness to be formed on the surfaceof the said thermoplastic resin skin material respectively can be surelykept approximately constant. Accordingly, the cellular molded article ofsynthetic resin having surface skin having more excellent appearancewithout beads pattern as is similar to an effect mentioned in the claim4 can be produced, and the present facility can be used as it is. Also,advantage is that, when this unevenness printing item material is to beremovable from the said one mold part, this can be utilized in variouskinds of facilities.

An essential feature residing in a method for producing a cellularmolded article of synthetic resin having a surface skin in whichcellular molded article of synthetic resin and thermoplastic resin skinmaterial are set between two mold parts, and when clamping parts andpressurizing them, these cellular molded article of synthetic resin andthermoplastic resin skin material are united by heat and/or adhesive,the fine unevenness of 5 to 150 μm in amplitude and 30 to 600 μm inwavelength of surface roughness waveshape measured by the surfaceroughness measuring instrument is formed in advance, and when unitingthe said cellular molded article of synthetic resin with thethermoplastic resin skin material, by printing the said fine unevennessto the surface of the thermoplastic resin skin material to make thesurface roughness of a prescribed range of thermoplastic resin skinmaterial which is pressed harder on the surface of the said one moldpart with pressurizing force and the surface roughness of the otherrange to be about the same, the surface roughness of this thermoplasticresin skin material is approximately kept in constant. Therefore, inso-called afterward attached molding, by printing the fine unevenness ofthe said one mold part with pressurizing force, the surface roughness offine unevenness formed respectively on the surface of the saidthermoplastic resin skin material can be surely kept approximatelyconstant. Accordingly, advantage of this invention is that the cellularmolded article of synthetic resin having surface skin and more excellentappearance without residing beads pattern can be produced.

An essential feature residing in a method for producing a cellularmolded article of synthetic resin having a surface skin in whichcellular molded article and thermoplastic resin skin material are setbetween two mold parts, and when clamping them and pressurizing them,these cellular molded article of synthetic resin and the thermoplasticresin skin material are united by heat and/or adhesive, unevennessprinting item material is attached in advance on the surface of one moldpart which will come in contact with the said thermoplastic resin skinmaterial, and when uniting the said cellular molded article of syntheticresin with the thermoplastic resin skin material, by printing the fineunevenness formed on the surface of the said unevenness printing itemmaterial having 5 to 150 μm in amplitude, 30 to 600 μm in wavelength ofsurface roughness waveshape measured by the surface roughness measuringinstrument to make the surface roughness of the thermoplastic resin of aprescribed range which is pressed harder to the surface of the saidunevenness printing item material by the above-mentioned pressurizingforce and the surface roughness of the other range to be about the samedegree on the surface of the thermoplastic resin skin material, thesurface roughness of this thermoplastic resin skin material isapproximately kept constant. Therefore, in so-called afterward attachedmolding, even in a case of attaching the unevenness printing itemmaterial, by printing the fine unevenness of this unevenness printingitem material with pressurizing force, the roughness of fine unevennessformed on the surface of the said thermoplastic resin skin material canbe surely kept approximately constant. Accordingly, the cellular moldedarticle of synthetic resin having surface skin and more excellentappearance without residing beads pattern can be produced as is similarto an effect mentioned in another embodiment and the present facilitiescan be used as it is. Also, advantage is that, when this unevennessprinting item material is removable from the said one mold part, thisitem material can be utilized in various kinds of facilities.

An essential feature is that the roughness of the said fine unevennesshas the waveform whose amplitude is in the range of 5 to 150 μm,wavelength is in the range of 30 to 600 μm measured by surface roughnessmeasuring instrument. Accordingly, in so-called simultaneous unitedmolding or afterward attached molding, by printing the fine unevennessof the said one mold part, the roughness of the fine unevenness formedon the surface of the said thermoplastic resin skin materialrespectively can be kept nearly constant in certain. Therefore, theappearance of the product can be improved more efficiently.

An essential feature is that in addition to the said fine unevenness,unevenness for product design pattern is formed in advance on thesurface of the said unevenness printing item material, and when printingthe said fine unevenness on the surface of the said thermoplastic resinskin material, the said unevenness for product design pattern is also tobe printed on. Therefore, in the so-called simultaneous united moldingor afterward attached molding, cellular molded article of syntheticresin having surface skin together with unevenness for product designpattern, which has more excellent appearance without residing beadspattern can be produced. Accordingly, advantage is that high-gradefeeling or the like can be added to the cellular molded article ofsynthetic resin having surface skin.

An essential feature is that in a method for producing a cellular moldedarticle of synthetic resin having a surface skin in which thermoplasticresin skin material is set on one of two mold parts which comprises themolding chamber and after clamping them, expanded beads are charged inthis molding chamber, expanded and melt bonded together by steam heatingalong with being melt bonded and united with the said thermoplasticresin skin material, the fine unevenness whose difference from the saidthermoplastic resin skin material is not more than 50 μm of amplitudeand not more than 200 μm of wavelength in surface roughness waveshapemeasured by the surface roughness measuring instrument is formed inadvance, and when melt bonding the said expanded beads together alongwith melt bonding and uniting these expanded beads with the saidthermoplastic resin skin material, by printing the said fine unevennesson the surface of the thermoplastic resin skin material to make thesurface roughness of a prescribed range of thermoplastic resin skinmaterial which is pressed harder to the surface of one mold part withexpanding force of the said expanded beads and the surface roughness ofother range to be about the same, the surface roughness of thisthermoplastic resin skin material is approximately kept in a constantlevel. Therefore, in so-called simultaneous united molding, by printingthe fine unevenness of the said one mold part with expanding force ofthe expanded beads, the roughness of fine unevenness formed on thesurface of the said thermoplastic resin skin material respectively canbe surely kept approximately in a constant level. Accordingly, acellular molded article of synthetic resin having surface skin and moreexcellent appearance without residing beads patterns can be produced.Moreover, since the beads pattern does not appear when the originalsurface roughness of the said thermoplastic resin skin material is veryrough or very fine, advantage is that various kinds of thermoplasticresin skin materials can be used

An essential feature is that in a method for producing a cellular moldedarticle of synthetic resin a having surface skin in which cellularmolded article of synthetic resin and thermoplastic resin skin materialare set in between two mold parts, and when clamping the parts andpressurizing them, these cellular molded article of synthetic resin andthermoplastic resin skin material are united by heat and/or adhesive,the fine unevenness whose difference from the said thermoplastic resinskin material is not more than 50 μm of amplitude and not more than 200μm of wavelength in surface roughness waveshape measured by the surfaceroughness measuring instrument is formed in advance, and when unitingthe said cellular molded article of synthetic resin with thethermoplastic resin skin material, by printing the said fine unevennessto the surface of the thermoplastic resin skin material to make thesurface roughness of a prescribed range of thermoplastic resin skinmaterial which is pressed harder to the surface of the said other onemold part by pressurizing force and the surface roughness of other rangeto be approximately the same, the surface roughness of thisthermoplastic resin is approximately kept in a constant level.Therefore, in so-called afterward attached molding, by printing the fineunevenness of the said one mold part with pressurizing force, theroughness of fine unevenness formed on the surface of the saidthermoplastic resin skin material respectively can be surely keptapproximately in a constant level. Accordingly, a cellular moldedarticle of synthetic resin having surface skin and having more excellentappearance without residing beads pattern can be produced. Also, sincethis beads pattern does not appear even when the original surfaceroughness of the said thermoplastic resin skin material is very rough orvery fine as is an effect mentioned in claim 10, various kinds ofthermoplastic resin skin material can be used.

An essential feature is that difference between the waveshape of theroughness of the said fine unevenness and that of the surface roughnessof the said thermoplastic resin skin material is not more than 50 μm ofamplitude, not more than 200 μm of wavelength measured by surfaceroughness measuring instrument. Therefore, in so-called simultaneousunited molding or afterward attached molding, various roughness of thefine unevenness formed on the surface of the said thermoplastic resinskin material can be by means of printing the fine unevenness of thesaid one mold part approximately kept in constant for certain.Therefore, the appearance of the product can be improved moreefficiently.

An essential feature is that the unevenness for product design patternin addition to the said fine unevenness is formed in advance on thesurface of the said one mold part, and the said unevenness for productdesign pattern as well as the said fine unevenness is printed on thesurface of the said thermoplastic resin skin material. Therefore, inso-called simultaneous united molding or afterward attached molding, acellular molded article of synthetic resin having surface skin andunevenness for product design pattern, having more excellent appearancewithout residing beads pattern can be produced. Accordingly, advantageis that high-grade feeling or the like can be added to the cellularmolded article of synthetic resin having surface skin.

An essential feature is that the unevenness for product design patternis formed in advance on the surface of the said thermoplastic resin skinmaterial before setting this thermoplastic resin skin material.Accordingly, in so-called simultaneous united molding or afterwardattached molding, the advantages are that the obtained cellular moldedarticle of synthetic resin having surface skin has more excellentappearance without residing beads pattern as the same effects mentionedin claim 9 and 13 and high-grade feeling or the like can be obtained bythe said unevenness for product design pattern. And since it is notnecessary to form unevenness for product design pattern on the surfaceof the said one mold part, the production cost can be reduced.

Furthermore, an essential feature residing in a mold used for producingcellular molded article of synthetic resin having surface skin of thisinvention is that in a mold used for producing a cellular molded articleof synthetic resin having a surface skin by a method in whichthermoplastic resin skin material is set on one of two mold parts whichcomprises a molding chamber and after clamping them, expanded beads arecharged in this molding chamber, then expanded and melt bonded togetherby steam heating along with being melt bonded and united with the saidthermoplastic resin skin material, fine unevenness having 5 to 150 μm ofamplitude, 30 to 600 μm of wavelength in surface roughness waveshapemeasured by the surface roughness measuring instrument is formed on thesurface of the said one mold part. Therefore, when using this mold partin so-called simultaneous united molding, as is similar to an effectmentioned in claim 4, advantage is that a cellular molded article ofsynthetic resin having surface skin and having more excellent appearancewithout residing beads pattern can be produced.

An essential feature is that in a mold used for producing a cellularmolded article of synthetic resin having a surface skin by a method inwhich cellular molded article of synthetic resin and thermoplastic resinskin material are set in between two mold parts, and when clamping theparts and pressurizing them, these cellular molded article of syntheticresin and thermoplastic resin skin material are united by heat and/oradhesive, the fine unevenness having not more than 5 to 150 μm ofamplitude, not more than 30 to 600 μm of wavelength in surface roughnesswaveshape measured by the surface roughness measuring instrument isformed on the surface of the one mold part which will come in contactwith the said thermoplastic resin skin material. Therefore, when usingthis mold in so-called afterward attached molding, an advantage is thata cellular molded article of synthetic resin having surface skin andmore excellent appearance without remaining beads pattern can beproduced.

An essential feature is that the roughness of the said fine unevennesshas waveshape whose amplitude is in the range of 5 to 150 μm, wavelengthis in the range of 30 to 600 μm measured by surface roughness measuringinstrument. Therefore, when using this mold in so-called same timeuniting molding or afterward attached molding, by printing the fineroughness of the said one mold part, the roughness of fine unevennessformed on the surface of the said thermoplastic resin skin materialrespectively can be approximately kept in constant level for certain.Accordingly, advantage is that the appearance of the product can beimproved more efficiently.

An essential feature is that in a mold used for producing cellularmolded article of synthetic resin having surface skin by a method inwhich thermoplastic resin skin material is set on one of two mold partswhich comprises molding chamber, and after clamping them, expanded beadsare charged in this molding chamber and then expanded and melt bondedtogether by steam heating along with being melt bonded and united withthe said thermoplastic resin skin material, fine unevenness whosedifference is not more than 50 μm of amplitude, not more than 200 μm ofwavelength in surface roughgness waveshape measured by the surfaceroughness measuring instrument is formed on the surface of the said onemold part. Therefore, when using this mold in so-called simultaneousunited molding, an advantage is that a cellular molded article ofsynthetic resin having surface skin and more excellent appearancewithout residing beads pattern can be produced. Also, since this beadspattern does not appear even when the original surface roughness of thesaid thermoplastic resin skin material is very rough or very fine,various kinds of thermoplastic resin skin material can be used.

An essential feature is that in a mold used for producing cellularmolded article of synthetic resin having surface skin by the method inwhich cellular molded article of synthetic resin and thermoplastic resinskin material are set in between two mold parts, and when clamping theparts and pressurizing them, these cellular molded article of syntheticresin and thermoplastic resin skin material are united by heat and/oradhesive, fine unevenness whose difference is not more than 50 μm ofamplitude, not more than 200 μm of wavelength in surface roughnesswaveshape measured by the surface roughness measuring instrument isformed on the surface of the one mold part which will come in contactwith the said thermoplastic resin skin material. Therefore, when usingthis mold in so-called afterward attached molding, a cellular moldedarticle of synthetic resin having surface skin and more excellentappearance without residing beads pattern can be produced. Moreover,since this beads pattern does not appear when the original surfaceroughness of the said thermoplastic resin skin material is very rough orvery fine, advantage is that various kinds of thermoplastic resin skinmaterials can be used.

An essential feature is that difference between the waveshape ofroughness of the said fine unevenness and the waveshape of the surfaceroughness of the said thermoplastic resin skin material is not more than50 μm of amplitude, not more than 200 μm of wavelength measured bysurface roughness measuring instrument. Therefore, using this mold inso-called simultaneous united molding or afterward attached molding, theroughness of the fine unevenness formed on the surface of the saidthermoplastic resin skin material respectively can be approximately keptin constant level for certain by printing fine unevenness of the saidone mold part. Accordingly, advantage is that the appearance of theproduct can be improved more efficiently.

An essential feature is that unevenness for product design pattern inaddition to the said fine unevenness is formed. Therefore, when usingthis mold in so-called simultaneous united molding or afterward attachedmolding, an advantage is that the obtained cellular molded article ofsynthetic resin having surface skin has more excellent appearancewithout residing beads pattern, and high-grade feeling or the like canbe attached additionally to the cellular molded article of syntheticresin having surface skin by the said unevenness for product designpattern.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional drawing of cellular molded article ofsynthetic resin having surface skin of embodiments.

FIG. 2 is a side cross-sectional explanatory drawing showing clampedstate of mold parts with forming and setting thermoplastic resin skinmaterial on one of the parts in a method for producing cellular moldedarticle of synthetic resin having surface skin of the embodiment 1.

FIG. 3 is a side cross-sectional explanatory drawing showing the way ofcharging expanded beads in the molding chamber.

FIG. 4 is a side cross-sectional explanatory drawing showing the way ofsupplying steam into the molding chamber after charging expanded beads.

FIG. 5 is a side cross-sectional explanatory drawing showing the way ofvacuum pumping from the molding chamber.

FIG. 6 is a side cross-sectional explanatory drawing showing cellularmolded state of expanded beads after supplying steam in the moldedchamber.

FIG. 7 is a side cross-sectional drawing of cellular molded article ofsynthetic resin having surface skin having edge part of the skinmaterial separated from the molding chamber.

FIG. 9 is a side cross-sectional explanatory drawing of clamped statewith setting thermoplastic resin skin material on the surface of onemold part in a method for producing cellular molded article of syntheticresin having surface skin of the embodiment 2.

FIG. 10 is a side cross-sectional enlarged drawing of necessary part toshow how the thermoplastic resin skin material of FIG. 9 is set.

FIG. 11 is a side cross-sectional enlarged drawing of necessary part toshow how expanded beads are cellular molded.

FIG. 12 is a side cross-sectional enlarged drawing of necessary part toshow the vicinity of the surface of the obtained cellular molded articleof synthetic resin having surface skin of this invention.

FIG. 13 is a side cross-sectional enlarged drawing of necessary part toshow how expanded beads are cellular molded in a method for producingcellular molded article of synthetic resin having surface skin of theembodiment 3.

FIG. 14 is a side cross-sectional enlarged drawing of necessary part toshow the vicinity of the surface of the obtained cellular molded articleof synthetic resin having surface skin.

FIG. 15 is a side cross-sectional enlarged drawing of necessary part toshow how expanded beads are cellular molded in a method for producingcellular molded article of synthetic resin having surface skin of theembodiment 4.

FIG. 16 is a side cross-sectional enlarged drawing of necessary part toshow how expanded beads are cellular molded in a method for producingcellular molded article of synthetic resin having surface skin of theembodiment 5.

FIG. 17 is a side cross-sectional enlarged drawing of necessary part toshow how expanded beads are cellular molded in a method for producingcellular molded article of synthetic resin having surface skin of theembodiment 6.

FIG. 18 is the same side cross-sectional enlarged drawing of necessarypart as FIG. 17 except the surface of the unevenness for product designpattern is approximately smoothed.

FIG. 19 is a side cross-sectional drawing showing the way of dampingwith setting cellular molded article of synthetic resin andthermoplastic resin skin material in between two mold parts in a methodfor producing cellular molded article of synthetic resin having surfaceskin of the embodiment 7.

FIG. 20 is a side cross-sectional enlarged drawing of necessary part toshow the state after clamping.

FIG. 21 is a side cross-sectional drawing showing the way of clampingwith setting thermoplastic resin skin material on the cellular moldedarticle of synthetic resin between in two mold parts with one of theparts being the upper part, and the other being the lower part.

FIG. 22 is a side cross-sectional enlarged drawing of necessary part toshow the state after clamping.

FIG. 23 is a side cross-sectional enlarged drawing of necessary part toshow the way of melt bonding and uniting cellular molded article ofsynthetic resin with thermoplastic resin skin material by heat whenpressurizing them in the condition of FIG. 20.

FIG. 24 is a side cross-sectional drawing of the obtained cellularmolded article of synthetic resin having surface skin.

FIG. 25 is a side cross-sectional enlarged drawing of necessary part toshow the vicinity of the surface of cellular molded article of syntheticresin having surface skin of FIG. 24.

FIG. 26 is a side cross-sectional enlarged drawing of necessary part toshow how cellular molded article of synthetic resin is melt bonded andunited with thermoplastic resin skin material by both heat and adhesivein a method for producing cellular molded synthetic resin having surfaceskin of the embodiment 8.

FIG. 27 is a side cross-sectional enlarged drawing of necessary part toshow the vicinity of the surface of the obtained cellular molded articleof synthetic resin having surface skin.

FIG. 28 is a side cross-sectional enlarged drawing of necessary part toshow how expanded beads are cellular molded in a conventional method(b).

FIG. 29 is a side cross-sectional enlarged drawing of necessary part toshow how is the beads pattern formed on the surface of the obtainedcellular molded article of synthetic resin having surface skin.

FIG. 30 is a side cross-sectional enlarged drawing of necessary part toshow how expanded beads are cellular molded in a conventional example(c).

FIG. 31 is a side cross-sectional enlarged drawing of necessary part toshow how cellular molded article of synthetic resin is melt bonded andunited with thermoplastic resin skin material by heat when clamping moldparts and pressurizing them in a conventional method (d).

BEST MODE FOR PRACTICING THE INVENTION

Embodiments of this invention are described below, based on thedrawings, and when the same composition as the mentioned prior art comesout, its explanation is abbreviated by using the prescribed mark. Inembodiments 1 to 6, the cases of applying so-called simultaneous unitedmolding are explained, and in embodiments 7 to 8, the cases of applyingso-called afterward attached molding are explained.

As shown in FIG. 1, a producing method of embodiment 1 is for producingcellular molded article of synthetic resin having surface skin 1 whichcomprises of cellular molded article of synthetic resin 2 andthermoplastic resin skin material 3 melt bonded and united with thesurface 2 a of the cellular molded article of synthetic resin 2.

This production method, as shown in FIGS. 2 to 7, is that in a methodfor producing a cellular molded article of synthetic resin havingsurface skin 1 in which thermoplastic resin skin material 3 formed inthis molding chamber 7 is set on one mold part 5 of two mold parts 5 and6 which comprises molding chamber 4 and after clamping the mold parts,expanded beads 8 are charged in this molding chamber 7, and expanded,melt bonded together by steam heating along with being melt bonded andunited with the said thermoplastic resin skin material 3, the part ofthe said one mold part 5 on which thermoplastic resin skin material 3 isset is, for example, made of gas permeable electron casted mold 5 dhaving fine gas permeable holes from some tens μm to a hundred μm on thewhole surface 5 a and the said one mold part 5 is made to be the upperpart, and the other part 6 is made to be the lower part during the saidsteam heating and before expanding the said expanded beads 8.

First, as shown in FIG. 2, the thermoplastic resin skin material 3formed in this molding chamber 7 is set on the said one mold part 5, andmold parts are clamped.

Here, the said molding chamber 4 comprises of two mold parts 5,6 whichcan be opened and clamped with a vertical motion, and the said one part5 is made to be the upper part, the other part 6 is made to be the lowerpart.

The said one mold part 5, for example, has concave shape in side crosssection forms chamber 5 b inside. And steam valve A1, decompressionvalve B1 and drain valve C1 are connected to the said chamber 5 brespectively.

The said the other mold part 6, for example, has convex shape in sidecross section, forms chamber 6 b inside and has a plurality of vaporholes 6 c on the surface 6 a side connecting to the said chamber 6 b.And steam valve A2, decompression valve B2 and drain valve C2 areconnected to the said chamber 6 b respectively, feeder 10 is set up tocharge expanded beads 8 into the said molding chamber 7.

As examples of the said thermoplastic resin skin material 3,thermoplastic resin sheet including a vinyl chloride resin orpolyolefine resin such as polyethylene resin, polypropylene resin can bementioned among others. And since this thermoplastic resin skin material3 is used as a surface skin of the cellular molded article of syntheticresin having surface skin 1, this thermoplastic resin skin material 3may be colored with a desired color by coloring toner and the likeaccording to the application.

Since this thermoplastic resin skin material 3 is set on the surface 5 aof the said one mold part 5 after formed in the said molding chamber 7,it is advantageous that a process to form this thermoplastic resin skinmaterial 3 in advance in other molding chamber or the like can beskipped. As for forming methods for this, for example, vacuum forming orslash forming can be mentioned among others.

The part of the said one mold part 5 on which thermoplastic resin skinmaterial 3 is set is, for example, made of gas permeable electron castedmold 5 d.

This gas permeable electric casted mold 5 d has gas permeability becauseof having numerous very fine gas permeable holes from some tens μm to ahundred μm of diameter connecting to the said chamber 5 b on the wholesurface 5 a, and it is, for example, produced by nickel electric castand the like. (e.g. PORASUDENTYU; trade name, made by KONAN TOKUSYUSANGYO Co.)

Thus, since the said gas permeable electric cast 5 d has such very finegas permeable holes from some tens to a hundred μm of diameter on thewhole surface 5 a, as is above-mentioned, when setting the saidthermoplastic resin skin material 3 on the said one mold part 5 byvacuum forming, the removability of the air or gas between this gaspermeable electric cast mold 5 d and the said thermoplastic resin skinmaterial 3 can be improved. Therefore, the said thermoplastic resin skinmaterial 3 can be stuck to the surface 5 a of the one mold part 5 morefirmly. And since the diameter of the said gas permeable holes is veryfine which is in the range from about some tens μm to 100 μm, advantageis also that the marks of these gas permeable holes are not printed onthe surface 3 a of the thermoplastic resin skin material 3.

And in place of the said gas permeable electric cast mold 5 d, a gaspermeable metal mold or a gas permeable ceramic mold (e.g. POSERAKKUSUII; trade name, made by SHINTOU KOGYO) having very fine gas permeableholes of about some μm of diameter on the whole surface 5 a made bysintering metal or ceramic particles under a prescribed condition can bealso used.

When it is necessary for the obtained cellular molded article ofsynthetic resin having surface skin 1 to have a mounting or the like,for example, for connecting with another member, an insert material of aprescribed shape (Not shown in Figures) may be set in advance on thesurface 6 a of the said the other mold part 6 and the said insertmaterial may be united with cellular molded article of synthetic resin 2produced by expanding and melt bonding the said expanded beads 8together when cellular molding of these expanded beads 8 is conducted.

Next, as shown in FIG. 3, expanded beads 8 are charged into the moldingchamber 7 from the said feeder 10. In this case, in order to chargeexpanded beads 8 more easily, the charging can be performed with keepingthe mold parts a little open (cracking), however, the width of theopening is not so wide to keep these expanded beads not to drop out.

As example of the synthetic resin comprising the said beads 8,polyolefine resin, polystyrene resin can be mentioned among others.

As example of the said polyolefine resin, polyethylene resin orpolypropylene resin such as low density polyethylene, middle densitypolyethylene, high density polyethylene, linear low densitypolyethylene, ethylene-vinyl acetate copolymer, propylene homopolymer,ethylene-propylene random copolymer, ethylene-propylene block copolymer,ethylene-propylene-butene random terpolymer, propylene-vinyl chloridecopolymer, propylene-butene copolymer, propylene-maleic anhydridecopolymer, poly(butene-1) can be mentioned among others, and these canbe used alone or as a mixture of not less than two.

This polyolefine resin is preferably not cross-linked, however, may becross-linked by using peroxide, radiation or the like.

Furthermore, a mixture of this polyolefine resin and other thermoplasticresin can be used. As examples of these thermoplastic resins, whenmixing with the said polypropylene resin, low density polyethylene,linear low density polyethylene, vinyl aromatic polymer, polybutene,ionomer can be mentioned among others, and when mixing with the saidpolyethylene resin, for example, vinyl aromatic polymer, polybutene,ionomer can be mentioned among others. And the amount of thethermoplastic resin to be mixed in these cases is preferably not morethan 20 parts by weight based on the 100 parts by weight of thepolyolefine resin, more preferably 5 to 10 parts by weight.

The said expanded beads 8 may be produced, for example, to be thepre-expansion by a method in which the said synthetic resin is processedto form particle shape in advance, impregnated with a volatile blowingagent in a pressure vessel, stirred while being dispersed in water,heated up under pressure to a prescribed expansion temperature, and thenthis water dispersion is released into a low pressure region or thelike. Among these expanded beads 8, for example, EPERAN PP (trade name;made by KANEGAFUCHI CHEMICAL INDUSTRY Co., Ltd., expansion ratio is 15times) can be suitably used among others.

In order to improve the adhesiveness of the said cellular molded articleof synthetic resin 2 obtained by cellular molding of these beads 8 andthermoplastic resin skin material 3, suitable adhesive can be appliedbeforehand to the backside surface 3 b of this thermoplastic resin skinmaterial 3 which will come in contact with the said expanded beads 8 ifnecessary. As example of this adhesive, an organic solvent solution ofsynthetic resin, a resin emulsion, a resin powder or the like can bementioned.

Then, as shown in FIG. 4, the steam valve A2 connected to the chamber 6b of the said the other mold part 6 is opened, and steam S is suppliedinto the molding chamber 7 through the said steam hole 6 c, and the saidexpanded beads 8 are heated and expanded.

At this point, by pre-heating the said expanded beads 8 in advance at atemperature lower than the temperature of melt bonding the said expandedbeads 8 together, before main heating of these expanded beads 8 at atemperature higher than the temperature of melt bonding the saidexpanded beads 8 together, these expanded beads 8 can be heatedsufficiently without melt bonding together.

And after the pre-heating, by keeping the condition for a prescribedtime and steaming the said expanded beads 8 by steam S (this is called“steaming”, hereinafter), the latent heat of steam S introduced amongthe said beads 8 can be utilized effectively. In particular in the caseof fabricating cellular molded article of synthetic resin having surfaceskin 2 which is very thick or the like, an advantage is that the saidexpanded beads 8 can be heated more uniformly. This “steaming” may becarried out in the condition of continuous introduction of steam S.Alternatively, the “steaming” may be carried out with suspending thesupply of steam S and with keeping the drain valve C2 open if necessary.And after performing “steaming” by steam S, drain (moisture) existsamong the pre-expanded beads 8, and since poor melt bonding of theexpanded beads 8 with each other can occur if main heating is carriedout in this condition, as shown in FIG. 5, for example, it is preferablethat the said drain in the molding chamber 7 is removed by vacuumpumping through the said vapor hole 6 c or the like.

And after performing “steaming” of the said expanded beads 8 by steam S,that is, during the said steam heating and before expanding the saidexpanded beads 8, since the said one mold part 5 is the upper part andthe said the other part 6 is the lower part, the said drain can beeasily taken out through the lower vapor hole 6 c by the above-mentionedvacuum pumping by utilizing the gravity power rather than going againstit Therefore, this drain can be surely removed and advantage is that nonor little drain remains in the said molding chamber 7.

Next, the main heating is carried out at a temperature higher than thetemperature at which said expanded beads 8 melt bonded together. Thismain heating is, as shown in FIG. 6, carried out by opening the saidsteam valve A2 and supplying steam S through the said vapor hole 6 cinto the molding chamber 7. And in the case of conducting vacuum pumpingin the said molding chamber 7 to remove drain after performing“steaming” by steam S as mentioned-above, the steam S for the said mainheating can be supplied into the molding chamber 7 more easily. Whenmain heating, in order to transfer enough heat by steam S to the saidexpanded beads 8, it is preferable to keep the condition for aprescribed time.

Next, by opening the mold after cooling the said molding chamber 4 orthe like, as shown in FIG. 7, cellular molded article of synthetic resinhaving surface skin la having the edge part 3 c, for example, whichcomprises of the cellular molded article of synthetic resin 2 obtainedby the cellular molding of the said expanded beads 8 and thermoplasticresin skin material 3 melt bonded and united with the surface 2 a of thecellular molded article of synthetic resin 2 is obtained. And thiscellular molded article of synthetic resin having surface skin 1 a ispreferable to be aged and dried after separated from the molding chamber4. And as is in this embodiment, when unnecessary part such as the saidedge part 3 c is formed at the end of the said thermoplastic resin skinmaterial 3 or the like, by cutting this edge part, cellular moldedarticle of synthetic resin having surface skin 1 shown in FIG. 1 can beobtained.

As above-mentioned, by main heating the said expanded beads 8 afterpre-heating and performing “steaming” by steam S, cellular moldedarticle of synthetic resin 2 can be melt bonded and united with the saidthermoplastic resin skin material 3 along with producing the cellularmolded article of synthetic resin 2 from expanded beads 8. And since thesaid drain can be surely removed, celular molded article of syntheticresin having surface skin 1 with having the said cellular molded articleof synthetic resin 2 without poor melt bonding of expanded beads 8 canbe produced.

In this embodiment 1, when setting the said thermoplastic resin skinmaterial 3 on the said one mold part 5, the said two mold 5,6 is openedand clamped with a vertical motion and the said one mold part 5 is theupper part, the other part 6 is the lower part, however, theseembodiments are not limited to this, but the above-mentioned conditionis kept at least during the said steam heating and before expanding thesaid expanded beads 8.

That means, for example, molding machine or the like that can change thedirection of opening or clamping of the said two die 5,6 can be used. Inthis case, for example, in order to set the said thermoplastic resinskin material 3 more easily, the said two mold parts can be opened andclamped with a horizontal motion at the start, or with a vertical motionwith the said one mold part 5 to be the lower part at the start andduring the said steam heating and before expanding the said expandedbeads 8, the said two mold parts are turned to be opened and clampedwith a vertical motion and the said one mold part 5 is turned to be theupper part, the other part 6 to be the lower part, as its result, thesaid drain can be removed easily. After removing the drain, the moldparts can be turned back to the original position again to separate theobtained cellular molded resin of synthetic resin having surface skin 1from the mold easily.

Moreover, before setting thermoplastic resin skin material 3 on the saidone mold part 5, the unevenness for product design pattern such as skinemboss can be formed in advance on the surface 3 a of the thermoplasticresin skin material 3 or when cellular molding of the expanded beads 8by the said steam heating, the unevenness for product design patternsuch as skin emboss formed in advance on the surface 5 a of the said onemold part 5 can be printed on the surface 3 a of the thermoplastic resinskin material 3.

As shown in FIG. 9 to FIG. 12, a method for producing cellular moldedarticle of synthetic resin 1 having surface skin of the embodiment 2comprises that the part on which the said thermoplastic resin skinmaterial 3 does not consist of the said gas permeable electron castedmold 5 d and that the said fine unevenness 9 having 5 to 150 μm ofamplitude, 30 to 600 μm of wavelength in surface roughness waveshapemeasured by the surface roughness measuring instrument is formed inadvance on the surface 5 a of the said one mold part 5 having pluralnumber of decompression hole 5 c connecting to the said chamber 5 b andthat when melt bonding the said expanded beads 8 along with melt bondingand uniting theses expanded beads 8 with the thermoplastic resin skinmaterial 3, by printing the said fine unevenness 9 onto the surface 3 aof the thermoplastic resin skin material 3 to make the surface roughnessof a prescribed range D of thermoplastic resin skin material 3 pressedharder to the surface 5 a of one mold part 5 with expanding force F ofthe said expanded beads 8 and the surface roughness of the other range Eto be approximately the same the surface roughness of this thermoplasticresin skin material 3 is kept approximately constant.

And as shown in FIG. 9, the said molding chamber 4, for example, can beopened and clamped with a horizontal motion in this embodiment, however,as is the said embodiment 1, the said one mold part 5 may be the upperpart and the other part 6 may be the lower part at least during the saidsteam heating and before expanding the said expanded beads 8. And thepart for setting thermoplastic resin skin material 3 on of the said onemold part 5 can be made of the said gas permeable electric cast mold 5d, gas permeable metal mold or gas permeable ceramic mold or the like.

As shown in FIG. 10, fine unevenness 19 is formed in advance on thesurface 3 a of the said thermoplastic resin skin material 3 by matprocessing of a prescribed roughness the same as is the case of normalcondition.

And the fine unevenness 9 having 5 to 150 μm of amplitude, 30 to 600 μmof wavelength in surface roughness waveshape measured by the surfaceroughness measuring instrument is formed in advance on the surface 5 aof the said one mold part 5. In order to form this fine unevenness 9,for example, various conventional techniques such as blast, etching canbe utilized.

When performing the said main heating, as shown in FIG. 11, theprescribed range D of the surface 3 a of the said thermoplastic resinskin material 3 is pressed against the surface 5 a of the said one moldpart 5 harder than the other range E from the backside 3 b by theexpanding force F of the said expanded beads 8. In this condition, sincethe said thermoplastic resin skin material 3 is softened by steamheating, as shown in FIG. 12, the said fine unevenness 9 formed inadvance on the surface 5 a of the said one mold part 5 is printed on,and the fine unevenness 9 d is formed on the said range D where pressedharder as above-mentioned,

Also, since the said the other range E is pressed against the surface 5a of the said one mold part 5 by force even smaller than that in rangeD, the said fine unevenness 9 is printed on the other range E and fineunevenness 9 e is formed. In this case, since the strength of the forcepressing against the surface 5 a of the said one mold part 5 isdifferent between in the said range D and in another range E, theroughness of the formed fine unevenness 9 d, 9 e respectively may bedifferent, however, by forming fine unevenness 9 of roughness in theabove-mentioned range in advance on the surface 5 a of the said one moldpart 5, the roughness of these fine unevenness 9 d and 9 e can be madeto be about the same pattern level. Accordingly, the surface roughnessof the said thermoplastic resin skin material 3 is approximately kept ina constant level, and it is advantageous that beads pattern as inconventional process does not appear and excellent appearance can beobtained more efficiently.

And it is preferable that the roughness of the said fine unevenness 9has waveshape of surface roughness in which amplitude is from 5 to 150μm, wavelength is from 30 to 600 μm, more preferably amplitude is from 7to 100 μm, wavelength is from 50 to 400 μm, most preferably amplitude isfrom 10 to 70 μm, wavelength is from 60 to 300 μm.

The surface roughness of the said range, for example, corresponds to theroughness from #1000 (No.1000) to #100 (No.100) compared to the surfaceroughness of sandpaper or the like.

As the example of the said surface roughness measuring instruments,touching needle type surface roughness measuring instrument (e.g. madeby TOKYO SEIMITSU Co, trade name: SAFUKOMU 570A, 5 μmR of the touchingneedle tip) or non-touching surface roughness measuring instrument (e.g.made by PERUTEN Co. Amp-part type: PERUTOMETER-S3P, sensor part type:non-touching probe, FOCODIN) can be mentioned among others.

When the roughness of the said fine unevenness 9 has a wavelength finerthan 5 μm of amplitude, 30 μm of wavelength, namely, the roughness ofthe said fine unevenness 9 is too fine, as is the afore-mentionedconventional example (b), it is not preferable because the beads patternappears as a result of the roughness of the fine unevenness 9 d of thesaid range D being finer than the roughness of the fine unevenness 9 eof the other range E. And when exceeding 150 μm of amplitude, 600 μm ofwavelength, namely, the roughness of the said fine unevenness 9 is toorough, conversely, it is also not preferable because the beads patternof opposite contrast to the above-mentioned appears as a result of theroughness of the said fine unevenness 9 d being rougher than the saidfine unevenness 9 e.

As shown in FIG. 13 and FIG. 14, a method for producing the cellularmolded article of synthetic resin having surface skin 21 of theembodiment 3 is that in the said embodiment 2, unevenness 12 for theproduct design in addition to the said fine unevenness 9 is formed inadvance on the surface 5 a of the said one mold part 5, and whenprinting the said fine unevenness 9 on the surface 3 a of the saidthermoplastic resin skin material 3, the said unevenness for productdesign pattern 12 is also printed.

As the example of the said unevenness for product design pattern 12, askin emboss can be mentioned among others. And the said fine unevenness9 may be also formed on the surface of this unevenness for productdesign pattern 12. This unevenness for product design pattern 12 can beformed by utilizing various conventional techniques. When forming theseunevenness for product design pattern 12 and fine unevenness 9 byetching, fine unevenness 9 is preferably formed after forming unevennessfor product design pattern 12 to let the said unevenness for productdesign pattern 12 appear clearly.

And on account of forming the said unevenness for product design pattern12, as shown in FIG. 13, even in the case of setting the saidthermoplastic resin skin material 3 with the gap H to the surface 5 a ofone mold part 5, since the whole thermoplastic resin skin material 3 ispressed against the said one mold part 5 at cellular molding the saidexpanded beads 8, the said unevenness for product design pattern 12 isprinted on the surface 3 a of the said thermoplastic resin skin material3, as shown in FIG. 14, and also the said fine unevenness 9 is printedand fine unevenness 9 d (9 e) is formed by performing the same operationas the embodiment 2. Accordingly, as is the above-mentioned embodiment2, when the roughness of the said fine unevenness 9 is made to be withinthe above-mentioned range the surface roughness of thermoplastic resinskin material 3 containing the said unevenness for product designpattern 12 is approximately kept in constant level.

Thus by forming the unevenness for product design pattern 12 in additionto the said fine unevenness 9 in advance on the surface 5 a of the saidone mold part 5, the cellular molded article of synthetic resin 21having unevenness for product design pattern 12 without residing beadspattern can be produced. Accordingly, the high-grade feeling or the likecan be added to the cellular molded article of synthetic resin havingsurface skin 21.

As shown in FIG. 15, a method for producing cellular molded article ofsynthetic resin having surface skin 1 of the embodiment 4 is that in theabove-mentioned embodiment 2, the unevenness printing item material 13is jointed in advance on the surface 5 a of the said one mold part 5,and when melt bonding the said expanded beads 8 together along with meltbonding and uniting these expanded beads 8 with the said thermoplasticresin skin material 3, the surface roughness of this thermoplastic resinskin material 3 is kept approximately kept in constant level by printingfine unevenness 9 formed on the surface 13 a of the said unevennessprinting item material 13 on the surface 3 a of the thermoplastic resinskin material 3 to make the surface roughness of a prescribed range ofthermoplastic resin skin material 3 which is pressed harder on thesurface 13 a of unevenness printing material 13 with expanding force Fof the said expanded beads 8 and the surface roughness of other range tobe approximately the same.

As examples of the said unevenness printing item material 13, metalboard, board of synthetic resin, sand cloth, sandpaper or waterresistant sand paper, net plane material made by metal or syntheticresin can be mentioned among others. And the said unevenness printingitem material 13 can be formed to fit the shape of the surface 5 a ofthe said one mold part 5, and on the surface 13 a, the unevenness 9 canbe formed by etching or blast or sticking micro particles or the like.Then with turning this fine unevenness 9 outside, the said unevennessprinting item material 13 is stuck to the surface 5 a of the said onemold part 5 in advance by adhesion of adhesive or the like or magneticsticking. The time of forming the said fine unevenness 9 and the time offorming this unevenness printing item material 13 to fit the shape ofthe surface 5 a of the said one mold part 5 are not particularlylimited. And plurality of connecting holes or the like getting throughthe decompressing hole 5 c of the said one mold part 5 can be formed ifnecessary.

Thus in the case of attaching the said unevenness printing item material13 on the surface 5 a of one mold part 5, by operating asabove-mentioned, the cellular molded article of synthetic resin havingsurface skin 1 as the embodiment 2 can be produced. Therefore,advantages are that the present facility can be utilized as it is andwhen this unevenness printing item material 13 is to be removable, alsoadvantage is that it can be utilized in various kinds of facilities.

And in this embodiment, the case when fine unevenness 9 is formed on thesurface 13 a of the said unevenness printing item material 13 isexplained, however, the scope of this invention is not limited to this,the unevenness for product design pattern 12 in addition to the saidfine unevenness 9 can be formed on the surface 13 a of the unevennessprinting item material materials 13 as the said embodiment 3.

As shown in FIG. 16, a method for producing the cellular molded articleof synthetic resin having surface skin 1 of the embodiment 5 is that inthe above-mentioned embodiment 2, after smoothing the surface 5 a of thesaid one mold part 5 on which fine unevenness 9 of the same roughness asthe above is formed in advance by sticking unevenness printing particlesubstance 14, the surface roughness of this thermoplastic resin skinmaterial 3 is approximately kept in constant level by printing the saidfine unevenness 9 to the surface 3 a of the thermoplastic resin skinmaterial 3 to make the surface roughness of thermoplastic resin skinmaterial 3 of a prescribed range which is pressed harder with expandingforce F of the said expanded beads 8 and the surface roughness of otherrange to be approximately the same when melt bonding of the saidexpanded beads 8 together and melt bonding and uniting these expandedbeads 8 with the said thermoplastic resin skin material 3.

As example of the said unevenness printing particle substance 14, metalpowder or the like can be mentioned, and the said unevenness printingparticle substance 14 can be stuck to the surface 5 a of the said onemold part 5 by adhesion of adhesives or the like or magnetic sticking.As for its particle size, the roughness of fine unevenness 9 formed bythis unevenness printing particle substance 14 can have waveshape inwhich amplitude is 5 to 150 μm, wavelength is 30 to 600 μm measured bythe afore-mentioned surface roughness measuring instrument.

Thus when forming fine unevenness 9 on the surface 5 a of the one moldpart 5 by utilizing the said unevenness particle substance 14, as theabove-mentioned embodiment 4, the cellular molded article of syntheticresin having surface skin 1 as in the embodiment 2 can be produced.Therefore, advantage is that the present facility can be utilized as itis.

And in this embodiment, the case when fine unevenness 9 is formed on thesurface 5 a of the said one mold part 5 by the said unevenness printingparticle substance 14, is explained, however, the scope of thisinvention is not limited to this, and as in the said embodiment 3,unevenness for product design pattern 12 in addition to the fineunevenness 9 formed by the said unevenness printing particle substance14 can be formed on the surface 5 a of the said one mold part 5.

As shown in FIG. 17, a method for producing cellular molded article ofsynthetic resin having surface skin 21 of the embodiment 6 is that inthe above-mentioned embodiment 2, the unevenness for product designpattern 12 is formed in advance on the surface 3 a of the thermoplasticresin skin material 3 before setting the thermoplastic resin skinmaterial 3 on the said one mold part 5.

As the methods for forming the unevenness for product design pattern 12on the surface 3 a of the said thermoplastic resin skin material 3, forexample, various conventional methods such as a method using embossingmachine can be utilized. And the surface of the said unevenness forproduct design pattern 12 can be formed to fine unevenness 19 by matprocessing as this embodiment or can be smoothed as shown in FIG. 18.

As shown in FIG. 17, by operating as the said embodiment 2 after settingthis thermoplastic resin skin material 3 on the surface 5 a of the saidone mold part 5, the said fine unevenness 9 is printed on the surface 3a of the thermoplastic resin skin material 3 to make the surfaceroughness of thermoplastic resin skin material 3 of a prescribed rangewhich is pressed harder on surface 5 a of one mold part 5 with expandingforce F of the said expanded beads 8 and the surface roughness of otherrange to be approximately the same. Consequently, the cellular moldedarticle of synthetic resin having surface skin 21 as in theabove-mentioned embodiment 3 shown in FIG. 14 can be produced.

Thus, even when unevenness for product design pattern 12 is formed inadvance on the surface 3 a of the said thermoplastic resin skin material3, as in the above-mentioned embodiment 3, advantages are that theappearance of the obtained cellular molded article of synthetic resinhaving surface skin 21 is excellent, and high-grade feeling or the likecan be added by the said unevenness for product design pattern 12.Moreover, since it is not necessary to form unevenness for productdesign pattern 12 on the surface 5 a of the said one mold part 5, thecost can be reduced.

And in this embodiment, the case when thermoplastic resin skin material3 having the said unevenness for product design pattern 12 is set on theone mold part 5 having fine unevenness 9 on the surface 5 a isexplained, however, the scope of this invention is not limited to this.As shown in the above-mentioned embodiment 4 or 5, the saidthermoplastic resin skin material 3 can be set on the unevennessprinting item material 13 attaching to the surface 5 a of the said onemold part 5 or can be set on the surface 5 a of the one mold part 5having fine unevenness 9 formed by the said unevenness printing particlesubstance 14.

In the embodiment 1 to 6, the case when the said one mold part 5 isconcave mold (female type) whose horizontal section is made concave isexplained, however the scope of this invention is not limited to this, amold comprising of one mold part 5 being convex mold (male type) whosehorizontal section is convex shape and the said other mold part 6 beingconcave mold (female type) whose horizontal section is concave shape canbe also used.

Next, the case of so-called afterward stuck molding is described.

As shown in FIGS. 19 to 25, a method for producing cellular moldedarticle of synthetic resin having surface skin 31 of the embodiment 7 isthat in a method for producing cellular molded article of syntheticresin having surface skin 31 in which cellular molded article ofsynthetic resin 2 and thermoplastic resin skin material 3 are setbetween two mold parts 15,16 and when clamping the two mold parts andpressurizing them, these cellular molded article of synthetic resin 2and thermoplastic resin skin material 3 are melt bonded and united, forexample, by heat, fine unevenness 9 of the same roughness as theabove-mentioned embodiment 2 is formed in advance on the surface 15 a ofone mold part 15 which will come in contact with the said thermoplasticresin skin material 3, and when melt bonding and uniting the saidcellular molded article of synthetic resin 2 with the said thermoplasticresin skin material 3, by printing the said fine unevenness 9 to makethe surface roughness of thermoplastic resin skin material 3 ofprescribed range D which is pressed harder on the surface 15 a of thesaid one mold part 15 with pressurizing force G and the surfaceroughness of the other range E to be approximately the same on thesurface 3 a of the thermoplastic resin skin material 3, the surfaceroughness of this thermoplastic resin skin material 3 is approximatelykept in constant level.

More precisely, as shown in FIG. 19, at the start, cellular moldedarticle of synthetic resin 2 and thermoplastic resin skin material 3 areset between the said two mold parts 15,16, and as shown in FIG. 20, themold parts are clamped.

The said two mold parts 15,16, for example, can be opened and clampedwith a vertical motion, one mold part 15 which will come in contact withthe said thermoplastic resin skin material 3 is set to be the lower moldpart and the other mold part 16 which will come in contact with the saidcellular molded article of synthetic resin 2 is set to be the upper moldpart. And concave mold part 15 d is formed to fit the shape of thesurface 2 a of the said cellular molded article of synthetic resin 2 onthe surface 15 a of the said one mold part 15, and the surface 16 a ofthe said the other mold part 16 is smoothed. Moreover, at least the saidone mold part 15 can be optionally made to be heated up to a prescribedtemperature by steam, electric heating element or the like.

The said cellular molded article of synthetic resin 2 is formed to be aprescribed shape in advance by cellular molding of the said expandedbeads 8.

In order to set the said thermoplastic resin skin material 3, forexample, the thermoplastic resin skin material 3 can be formed inadvance to fit the shape of the surface 15 a of the said one mold part15 by vacuum forming or the like using other molding chamber or thelike. Alternatively, without pre-forming or the like, for example, asshown in FIGS. 21 and 22, the said one part 15 is made to be the uppermold part and the said the other part 16 is made to be the lower moldpart and the said thermoplastic resin skin material 3 can be set on topof the cellular molded article of synthetic resin 2. In this case, whenclamping and pressurizing the two mold parts 15,16 as shown in FIG. 22,the two mold parts 15,16 are preferably heated up for easy forming.

Next, as shown in FIG. 23, in the condition of FIG. 20, whenpressurizing the mold by pressurizing force G, the said cellular moldedarticle of synthetic resin 2 and thermoplastic resin skin material 3 aremelt bonded and united by heat. In this case, the heating can beperformed in any time selected from before setting cellular moldedarticle of synthetic resin 2 and thermoplastic resin skin material 3,after setting these materials, after clamping the mold, afterpressurizing the mold or at the same time as setting, clamping orpressurizing. Possibly, the heating may be performed in advance to aprescribed temperature, and at a prescribed stage, temperature may beraised to the temperature at which cellular molded article of syntheticresin 2 and thermoplastic resin skin material 3 are melt bonded.Possibly, the heating may be performed in advance up to at a temperaturehigher than the temperature at which these cellular molded article ofsynthetic resin 2 and thermoplastic resin skin material 3 are meltbonded and at a prescribed stage the heating may be stopped and meltbonding may be performed by the kept heat. In any method, it isimportant to be able to melt bond and unite cellular molded article ofsynthetic resin 2 and thermoplastic resin skin material 3 atpressurizing.

And when the mold parts are opened after cooling or the like, as shownin FIG. 24, cellular molded article of synthetic resin having surfaceskin 31 canbe obtained.

Moreover, fine unevenness 19 is formed in advance on the surface 3 a ofthe said thermoplastic resin skin material 3 by mat processing with aprescribed roughness as is in the normal condition as shown in FIG. 23.And fine roughness 9 having 5 to 150 μm of amplitude, 30 to 600 μm ofwavelength of surface roughness waveshape measured by the said surfaceroughness measuring instrument is formed in advance on the surface 15 aof the said one mold part 15.

In this case, since the surface 2 a of the said cellular molded articleof synthetic resin 2 is not smoothed, by pressurizing force G, aprescribed range D of the surface 3 a of the said thermoplastic resinskin material 3 is pressed harder than the other range E against thesurface 15 a of the said one mold part 15 from the backside 3 b. In thiscase, as the above-mentioned embodiment 2, since the said thermoplasticresin skin material 3 is softened by heat in this condition, as shown inFIG. 25, by printing the said fine unevenness 9 formed in advance on thesurface 15 a of the said one mold part 15, fine unevenness 9 d is formedin the said range D.

Also, since the said the other range E is pressed against the surface 15a of the said one mold part 15 by a force smaller than the force to therange D, the said fine unevenness 9 e is formed in this the other rangeE by printing the said fine unevenness 9. In this case, also, since theroughness of the said fine unevenness 9 is made to be in theabove-mentioend range, the roughness of the said fine unevenness 9 d, 9e can be approximately the same level. Consequently, the surfaceroughness of the said thermoplastic resin skin material 3 isapproximately kept in constant level, and it is advantageous that theprevious beads pattern does not appear and that appearance of itsproduct can be improved more.

As shown in FIGS. 26 and 27, a method for producing cellular moldedarticle of synthetic resin having surface skin 41 of the embodiment 8 isthat in the above-mentioned embodiment 7, with putting adhesive 17between the said cellular molded article of synthetic resin 2 andthermoplastic resin skin material 3, the melt bonding and uniting thecellular molded article of synthetic resin 2 and thermoplastic resinskin material 3 by both heat and adhesive 17.

As the example of the said adhesive 17, as is in the case of the saidsimultaneous united molding, for example, a synthetic resin dissolved inan organic solvent, a resin emulsion, a resin powder or the like can bementioned. This adhesive 17 may be applied in advance to the backside 3b of the thermoplastic resin skin material 3 or the surface 2 a of thesaid cellular molded article of synthetic resin 2.

In the case of using a method in which the said cellular molded articleof synthetic resin 2 and thermoplastic resin skin material 3 are setbetween two mold parts 15,16 and when clamping and pressurizing two moldparts, these are melt bonded and united by heat and adhesive, as shownin FIG. 26, as is the above-mentioned the embodiment 7, since thesurface 2 a of the said cellular molded article of synthetic resin 2 isnot smoothed, the prescribed range D of the surface 3 a of the saidthermoplastic resin skin material 3 is pressed harder than the otherrange E by pressurizing force G. Therefore, as shown in FIG. 27, byprinting fine unevenness 9 on the surface 3 a of this thermoplasticresin skin material 3, fine unevenness 9 d, 9 e are formed. Since thesaid fine unevenness 9 is made to be in the above-mentioned range, theroughness of fine unevenness 9 d, 9 e can be made to be about the same.Consequently, the beads pattern does not appear.

Thus, when using the said adhesive 17, the adhesiveness between the saidcellular molded article of synthetic resin 2 and thermoplastic resinskin material 3 can be improved. And when using the suitable adhesive17, adhering can be performed even at a temperature below melting pointof the said cellular molded article of synthetic resin 2. Therefore,advantage is that heating to so high temperature is not needed.

And in this embodiment, cellular molded article of synthetic resin 2 andthermoplastic resin skin material 3 are melt bonded and united by bothheat and adhesive 17, however, the scope of this invention is notlimited to this, these can be bonded and united by adhesive 17 withoutheat. As adhesive 17 in this case, adhesive which has adhesiveness at aroom temperature or which cures at room temperature or the like can beused. Thus when uniting by adhesive 17, as is above-mentioned, fineunevenness of approximately the same roughness 9 d, 9 e are formed onthe surface 3 a of the said thermoplastic resin skin material 3 bypressurizing force G. Consequently, the beads pattern does not appear.

And in the embodiment 7 and 8, the said two mold parts 15,16 are made tobe opened and clamped with a vertical motion, however, the scope of thisinvention is not limited to this, and the mold parts also can be openedand clamped with a horizontal motion.

And the case when fine unevenness 9 is formed on the surface 15 a of thesaid one mold part 15 is described, however, the scope of this inventionis not limited to this, as is the above-mentioned embodiments 3 to 6,unevenness for product design pattern 12 in addition to the said fineunevenness 9 can be formed in advance on the surface 15 a of the saidone mold part 15 or unevenness for product design pattern 12 can beformed in advance on the surface 3 a of the said thermoplastic resinskin material 3. Furthermore, the said unevenness printing item material13 can be used or the said fine unevenness 9 can be formed by unevennessprinting particle substance 14.

As above-mentioned, in the embodiments 2 to 8, the case when the surface3 a of the said thermoplastic resin skin material 3 is mat processedwith an appropriate roughness is described, but the surface roughness ofthis thermoplastic resin skin material 3 is not particularly limited tothis, it can also be applied to very rough or very fine.

That means, even in the case of being very rough or very fine, by makingthe roughness of the said fine unevenness 9 to be adjusted to about thesame as the original surface roughness of the said thermoplastic resinskin material 3 in advance, the roughness of the fine unevenness 9 d, 9e formed in the said range D and the other range E respectively at thesaid simultaneous united molding or afterward attached molding can bemade to about the same. Consequently, the surface roughness of the saidthermoplastic resin skin material 3 is approximately kept in constantlevel, and the previous beads pattern does not appear. Therefore,advantage is that various kinds of thermoplastic resin skin material 3can be used.

Here, the roughness of the said fine unevenness 9 and the surfaceroughness of the said thermoplastic resin skin material 3 are mostpreferably the same. However, when these are not the same, thedifference of waveshape between them is not more than 50 μm ofamplitude, not more than 200 μm of wavelength, preferably not more than40 μm of amplitude, not more than 150 μm of wavelength, more preferablynot more than 30 μm of amplitude, not more than 100 μm of wavelengthmeasured by surface roughness measuring instrument. And in this caseeither one of them can be rougher than the other.

The difference mentioned here is decided by comparing the amplitude andwavelength respectively, and means the maximum value calculated by thedifferences of both amplitude and wavelength becoming maximum.

When the said difference is within the above mentioned range, theroughness of the said fine unevenness 9 d, 9 e formed on the surface 3 aof the said thermoplastic resin skin material 3 by printing the saidfine unevenness 9 can be approximately the same for certain.Consequently, advantage is that the appearance of the product can beimproved still more efficiently. And when the surface roughness of thesaid one mold part 5 and thermoplastic resin skin material 3 are thesame or very similar, naturally printing the said fine unevenness 9 isnot necessarily essential to achieve the above mentioned object whichaims not to appear the beads pattern. Whereas, for example, whenunevenness for product design pattern 12 such as skin emboss is formedon the surface 5 a of the said one mold part 5, printing this unevennessfor product design pattern 12 is essential, and the cases when printingthe said fine unevenness 9 is not necessarily essential are alsoinvolved in production of the cellular molded article of synthetic resinhaving surface skin 1, 21, 31, or 41.

When the difference of the waveshape between the roughness of the saidfine unevenness 9 and the surface roughness of the said thermoplasticresin skin material 3 exceeds both 50 μm of amplitude and 200 μm ofwavelength and the surface roughness of the said thermoplastic resinskin material 3 is rougher, the roughness of fine unevenness 9 d of thesaid range D becomes finer than the roughness of fine unevenness 9 e ofthe other range E, and appears the beads pattern, which is notpreferable. Conversely, when the surface roughness of the saidthermoplastic resin skin material 3 is finer, the roughness of the saidfine unevenness 9 d becomes rougher than the roughness of the said fineunevenness 9 e, and appears the beads pattern of the opposite contrast,which is also not preferable.

And as above-mentioned, when the roughness of the said fine unevenness 9and the surface roughness of the said thermoplastic resin skin material3 are about the same, these roughness are not particularly limited,these can also be very rough or very fine. The roughness of the casewhen being very rough corresponds to the above mentioned waveshapeexceeding both about 150 μm of amplitude and about 600 μm of wavelength.And the roughness of the case when being very fine corresponds to theabove-metioned waveshape which is less than about 5 μm of amplitude,less than about 30 μm of wavelength. When these values are compared tothe surface roughness of the sandpaper or the like, for example, thesaid case of being very rough corresponds to the case of being rougherthan about #100 (No.100), the said case of being very fine correspondsto the case of being finer than about #1000 (No.1000).

That means when the both roughnesses are about the same, any roughnesscan be permitted. And the case when both the surface 5 a of the said onemold part 5 and the surface 3 a of the said thermoplastic resin skinmaterial 3 are formed to approximate smoothness and the roughness of thesaid fine unevenness 9,19 are ultra fine is also involved in the case ofbeing very fine.

Next, this invention is further illustrated by the following examples,however, the scope of this invention is not limited to these examples.

EXAMPLE 1

A laminated sheet made of a vinyl chloride resin sheet (thickness: 0.5mm) with a polypropylene resin extruded foam sheet (thickness: 2.5 mm)was used as the thermoplastic resin skin material, and one of two moldparts composing the molding chamber was set to be the upper mold partand the other mold part was set to be the lower mold part, and vacuumforming of the thermoplastic resin skin material was performed in amanner that one mold part to stick the said vinyl chloride surface ontothe surface of the one mold part. And after clamping mold parts, EPERANPP (trade name, made by KANEGAFUCHI CHEMICAL INDUSTRY Co. Ltd.,expansion ratio was 15 times, imparted with 2 kg/cm² of inner pressurein advance by using air pressure) as expanded beads were charged intothe molding chamber.

Next, steam (0.7 kg/cm²·G) was supplied into the molding chamber throughvapor holes formed in the said the other mold part, and pre-heating wasperformed. After the “steaming” of expanded beads for 5 seconds, drainand steam were removed to make the pressure in the molding chamber lessthan 500 mmHg by using vacuum pump.

Then, steam (3.2 to 3.7 kg/cm²·G) was supplied into the molding chamberagain through the said vapor holes, and after main heating by keepingfor 3 to 5 seconds, it was cooled by water, and cooled by room air, andthen the mold parts were separated to open and the cellular moldedsynthetic resin having surface skin was obtained.

EXAMPLE 2

The conditions of Example 2 were the same as those of Example 1 exceptfor using a laminated sheet of polyolefin resin sheet (thickness: 0.75mm) with polypropylene extruded foam sheet (thickness: 2.5 mm) asthermoplastic resin skin material, and without performing “steaming”.Under such conditions the cellular molded article of synthetic resinhaving surface skin was obtained.

EXAMPLE 3

The conditions of Example 3 were the same as those of Example 1 exceptusing EPERAN PP (trade name, made by KANEGAFUCHI CHEMICAL INDUSTRY Co.Ltd., imparted with 2 kg/cm² of inner pressure in advance by using airpressure) whose expansion ratio was 30 times as expanded beads, andsupplying steam of pressure 0.5 kg/cm²·G at pre-heating and supplyingsteam with pressure of 2.4 to 2.8 kg/cm²·G at main heating. Under suchconditions the cellular molded article of synthetic resin having surfaceskin was obtained.

EXAMPLE 4

The conditions of Example 4 were the same as those of Example 3 exceptusing a laminated sheet of polyolefin resin sheet (thickness: 0.75 mm)with a polypropylene resin extruded foam sheet (thickness: 2.5 mm),without performing “steaming”. Under such conditions the cellular moldedarticle of synthetic resin having surface skin was obtained.

COMPARATIVE EXAMPLE 1

The conditions of Comparative Example 1 were the same as those ofExample 1 except the said one mold part was set to be the lower moldpart and the other mold part was set to be the upper mold part. Undersuch conditions the cellular molded article of synthetic resin havingsurface skin was obtained.

COMPARATIVE EXAMPLE 2

The conditions of Comparative Example 2 were the same as those ofExample 2 except the said one mold part was set to be the lower moldpart and the other mold part was set to be the upper mold part. Undersuch conditions the cellular molded article of synthetic resin wasobtained.

COMPARATIVE EXAMPLE 3

The conditions of Comparative Example 3 were the same as those ofExample 3 except the said one mold part was set to be the lower moldpart and the other mold part was set to be the upper mold part. Undersuch conditions the cellular molded article of synthetic resin havingsurface skin was obtained.

COMPARATIVE EXAMPLE 4

The conditions of Comparative Example 4 were the same as those ofExample 4 except the said one mold part was set to be the lower moldpart and the other mold part was set to be the upper mold part. Undersuch conditions the cellular molded article of synthetic resin havingsurface skin was obtained.

As the physical properties of the cellular molded articles of syntheticresin having surface skin obtained in Examples 1 to 4 and ComparativeExamples 1 to 4, (a) melt bonding ratio of expanded beads, (b)adhesiveness between the cellular molded article of synthetic resin andthe thermoplastic resin skin material were evaluated by the followingmethods. The results were shown in Table 1.

(a) Melt bonding ratio of expanded beads

Using a knife, a thin cut was made on the surface of the obtainedcellular molded article of synthetic resin having surface skin, then thearticle was bent and broken, and the broken surface state was observed.The proportion of the broken expanded beads area to the whole area wasshown in percentage, and ranked by the evaluation standard shown below.

[Evaluation standard]

A: Melt bonding ratio of expanded beads is not less than 60%

B: Melt bonding ratio of expanded beads is 40 to 59%

C: Melt bonding ratio of expanded beads is 20 to 39%

D: Melt bonding ratio of expanded beads is not more than 19%

(b) Adhesiveness between cellular molded article of synthetic resin andthermoplastic resin skin material

The thermoplastic resin skin material and the cellular molded article ofsynthetic resin composed in the obtained cellular molded article ofsynthetic resin having surface skin were peeled off, and the interfacedstate was observed, and ranked by the evaluation standard shown below.

[Evaluation standard]

A: Only material break in the layer of cellular molded article ofsynthetic resin is observed.

B: Both material break in the cellular molded article of synthetic resinlayer and peeling off at the interface of the cellular molded article ofsynthetic resin layer and thermoplastic resin skin material areobserved.

C: Peeling off at the interface of the cellular molded article ofsynthetic resin layer and the thermoplastic resin skin material isobserved.

D: The cellular molded article of synthetic resin layer andthermoplastic resin skin material are not adhered therewith.

TABLE 1 Physical properties of the cellular molded article of syntheticresin having surface skin Adhesiveness between the cellular moldedarticle of synthetic resin Melt bonding ratio of and the thermoplasticresin skin expanded beads material Example 1 A A Example 2 A A Example 3A A Example 4 A A Comparative B to D C to D Example 1 Comparative B to DC to D Example 2 Comparative B to D C to D Example 3 Comparative B to DC to D Example 4

EXAMPLE 5

One of the two mold parts which is composing the molding chamber wasmade to be a female type and the other mold part was made to be a maletype. The porous sintering metal was used for the said one mold part tomake gas permeable holes of air, and fine unevenness was formed inadvance on its surface by chemical etching treatment. The surfaceroughness of this fine unevenness had a waveshape in the range of 20 to30 μm of amplitude, 150 to 200 μm of wavelength measured by touchingneedle type surface roughness measuring instrument (made by TOKYOSEIMITSU Co., trade name: SAFUKOMU 570A, touching needle tip by 5 μmR).

Polyolefinic thermoplastic resin sheet (TPO sheet) was used as thethermoplastic resin skin material, and after heating and softening, thesheet was set on the said one mold part, and formed by vacuum pump.

EPERAN PP (made by KANEGAFUCHI CHEMICAL INDUSTRY Co. Ltd., trade name,expansion ratio was 15 times, imparted with 2 kg/cm² of inner pressureby air pressure in a pressure vessel in advance) was used as theexpanded beads, and after clamping the mold parts, these expanded beadswere charged into the molding chamber.

Next, steam (steam pressure 1.5 kg/cm²·G) was supplied into the moldingchamber through vapor holes formed in the said the other mold part, andpre-heating was performed. After performing “steaming” of expandedbeads, drain and steam were removed by vacuum pump.

Then, steam (steam pressure 3.2 to 3.7 kg/cm²·G) was supplied into themolding chamber again through the said vapor holes, and after mainheating, cooled by water, the mold parts were separated to open and thecellular molded article of synthetic resin having surface skin wasobtained.

EXAMPLE 6

Unevenness for product design pattern was formed in advance by chemicaletching treatment on the surface of the said one mold part, then, fineunevenness was formed as same as in Example 1. Other conditions ofExample 6 were the same as those of Example 5 except using this moldpart, and the cellular molded article of synthetic resin having surfaceskin was obtained.

EXAMPLE 7

The conditions of Example 7 were the same as those of Example 5 exceptsetting the thermoplastic resin skin material formed to fit the said onemold part in advance, and the cellular molded article of synthetic resinhaving surface skin was obtained.

EXAMPLE 8

The conditions of Example 8 were the same as those of Example 5 exceptsteam heating was performed from the said one mold part side along withsupplying steam (steam pressure 3.2 to 3.7 kg/cm²·G) through vapor holesin the said the other mold part at main heating, and the cellular moldedarticle of synthetic resin having surface skin was obtained.

EXAMPLE 9

The conditions of Example 9 were the same as those of Example 5 exceptsandpaper of #600 (No.600) whose surface was formed to fine unevennesswas used as an unevenness printing item material, and this sandpaper wasstuck to the surface of the said one mold part in advance, and thecellular molded article of synthetic resin having surface skin wasobtained. And the surface roughness of fine unevenness of sandpaper hada waveshape which was 10 to 30 μm of amplitude, 100 to 200 μm ofwavelength measured by the said touching needle type surface roughnessmeasuring instrument. And a plurality of fine gas permeable holes whichwere not more than about 0.2 mm were made on the sandpaper in advance.

EXAMPLE 10

The conditions of Example 10 were the same as those of Example 5 exceptfine unevenness were formed on the surface of the said one mold part byblast processing (#120, shot pressure of 10 kg/cm²), and the cellularmolded article of synthetic resin having surface skin was obtained. Andthe surface roughness of the fine unevenness by the said blastprocessing had a waveshape which was 10 to 20 μm of amplitude, 80 to 200μm of wavelength measured by the said touching needle type surfaceroughness measuring instrument.

EXAMPLE 11

Expanded beads used in this example were the same EPERAN PP (made byKANEGAFUCHI CHEMICAL INDUSTRY Co. Ltd., trade name, expansion ratio was15 times, imparted with 2 kg/cm² of inner pressure by air pressure inthe pressure vessel in advance) as those used in Example 5, and bycellular molding, the cellular molded article of synthetic resin of aprescribed shape was formed in advance. And thermoplastic resin skinmaterial used in this example was the same polyolefinic thermoplasticresin sheet (TPO sheet) as same as those used in Example 5, and anadhesive was applied to one surface of this sheet in advance.

One mold part whose surface was formed to fine unevenness of the samesurface roughness as that of Example 5 in advance by chemical etchingtreatment was made to be the upper mold part and the other mold part tobe the lower mold part. And the said cellular molded article ofsynthetic resin was set on the other mold part, and after heating andsoftening thermoplastic resin skin material, and then the thermoplasticresin skin material was set on the cellular molded article of syntheticresin to make of which adhesive applied surface to contact with thecellular molded article of synthetic resin.

Next, while heating the said one mold part, the mold parts were clamped,and pressurized by 2 kg/cm² of pressurizing force, and the cellularmolded article of synthetic resin was obtained.

COMPARATIVE EXAMPLE 5

The conditions of Comparative example 5 were the same as those ofExample 5 except the surface of the said one mold part was smoothedwithout forming fine unevenness, and the cellular molded article ofsynthetic resin having surface skin was obtained.

COMPARATIVE EXAMPLE 6

The conditions of Comparative example 6 were the same as those ofExample 11 except the surface of the said one mold part was smoothedwithout forming fine unevenness, and the cellular molded article ofsynthetic resin having surface skin was obtained.

The surface appearance of the cellular molded article of synthetic resinhaving surface skin obtained by Examples 5 to 11 and Comparativeexamples 5 to 6 were observed, and ranked by the following evaluationstandard. The results were shown in Table 2.

[Evaluation Standard]

∘: The beads pattern did not appear on the surface of thermoplasticresin skin material.

X: The beads pattern appeared on the surface of thermoplastic resin skinmaterial.

TABLE 2 The surface appearance of the cellular molded article ofsynthetic resin having surface skin Example 5 ◯ Example 6 ◯ Example 7 ◯Example 8 ◯ Example 9 ◯ Example 10 ◯ Example 11 ◯ Comparative example 5X Comparative example 6 X

EXAMPLE 12

The conditions of Example 12 were the same as those of Example 5 exceptthe surface roughness of the said fine unevenness had a waveshape whichwas 20 to 30 μm of amplitude, 150 to 250 μm of wavelength measured bythe said touching needle type surface roughness measuring instrument,and polyolefinic thermoplastic resin skin material sheet TPO sheet)which was formed in advance to fit the surface shape of the said onemold part was set on the said one mold part, the cellular molded articleof synthetic resin having surface skin was obtained.

Therein the surface roughness of the said thermoplastic resin skinmaterial had a waveshape which was 10 to 30 μm of amplitude, 100 to 300μm of wavelength measured by the said touching needle type surfaceroughness measuring instrument. The difference of the said waveshapebetween the roughness of the said fine unevenness and the surfaceroughness of this thermoplastic resin skin material was 20 μm ofamplitude, 150 μm of wavelength.

EXAMPLE 13

Unevenness for product design pattern was formed on the surface of thesaid one mold part in the same way as Example 6, then fine unevennesswas formed in the same way as Example 12. Other conditions of Example 13were the same as those of Example 12 except using this mold part, andthe cellular molded article of synthetic resin having surface skin wasobtained.

EXAMPLE 14

The conditions were the same as those of Example 12 except steam wassupplied into the molded chamber through vapor holes of the said theother mold part in the same way as Example 8 at the main heating andsteam heating was performed from the said one mold part side, and thecellular molded article of synthetic resin having surface skin wasobtained.

EXAMPLE 15

The conditions of Example 15 were the same as those of Example 12 exceptsandpaper of #600 (No.600) which was the same as that of Example 9 wasused as unevenness printing item material, and stuck to the surface ofthe said one mold part in advance, and the cellular molded article ofsynthetic resin having surface skin was obtained.

And the difference of the said waveshape between the roughness of fineunevenness of the said sandpaper and the surface roughness of the saidthermoplastic resin skin material was 20 μm of amplitude, 200 μm ofwavelength.

EXAMPLE 16

EPERAN PP (made by KANEGAFUCHI CHEMICAL INDUSTRY Co. Ltd., trade name,expansion ratio was 15 times, imparted with 2 kg/cm² of inner pressureby air pressure in the pressure vessel in advance) which was the same asthat of Example 12 was used as expanded beads, and by cellular molding,cellular molded article of synthetic resin of a prescribed shape wasformed in advance. And polyolefinic thermoplastic resin sheet (TPOsheet) which was the same as those of Example 12 was used as thethermoplastic resin skin material, and adhesive was applied to the onesurface of the sheet in advance.

In two mold parts, one mold part whose surface was formed in advance tofine unevenness of the same roughness as that of Example 12 by chemicaletching treatment was set to be the upper mold part and the other moldpart to be the lower mold part, and other conditions were the same asthose of Example 11, and the cellular molded article of synthetic resinhaving surface skin was obtained.

EXAMPLE 17

A polyolefinic thermoplastic resin sheet (TPO sheet) which was the sameas that of Example 12 was set on the lower side of the heat pressmachine, and pressurized by 2 kg/cm² of pressurizing force for 50seconds while heating to 150° C., as a result, the surface of thethermoplastic resin skin material was approximately smoothed.

And the surface roughness of this thermoplastic resin skin material hada waveshape which was 0.1 to 0.5 μm of amplitude, 10 to 30 μm ofwavelength measured by the said touching needle type surface roughnessmeasuring instrument.

A mold part whose surface was approximately smoothed was used as thesaid one mold part.

And the surface roughness of this mold part had the waveshape which was0.1 to 0.3 μm of amplitude, 2 to 10 μm of wavelength. That means, thedifference of the said waveshape between the surface roughness of thisone mold part and the surface roughness of the said thermoplastic resinskin material was 0.4 μm of amplitude, 28 μm in wavlength.

Other conditions were the same as those of Example 12 except using thesaid thermoplastic resin skin material whose surface was approximatelysmoothed and one mold part whose surface was approximately smoothed asabove-mentioned, and the cellular molded article of synthetic resinhaving surface skin was obtained.

COMPARATIVE EXAMPLE 7

The conditions of Comparative example 7 was the same as those of Example12 except using one mold part whose surface was approximately smoothedin the same way as Example 17, and the cellular molded article ofsynthetic resin having surface skin was obtained.

COMPARATIVE EXAMPLE 8

The conditions of Comparative example 8 were the same as those ofExample 12 except using the same thermoplastic resin skin material whosesurface was nearly smoothed as that used in Example 17, and the cellularmolded article of synthetic resin having surface skin was obtained.

COMPARATIVE EXAMPLE 9

The conditions of Comparative example 9 were the same as those ofExample 16 except using the same one mold part whose surface was nearlysmoothed as that used in Example 17, and the cellular molded article ofsynthetic resin having surface skin was obtained.

COMPARATIVE EXAMPLE 10

The conditions of Comparative example 10 were the same as those ofExample 16 except using the same thermoplastic resin skin material whosesurface was nearly smoothed as used in Example 17, and the cellularmolded article of synthetic resin having surface skin was obtained.

The surface appearances of the cellular molded articles of syntheticresin having surface skin obtained in Example 12 to 17, Comparativeexample 7 to 10 were observed, and ranked by the said evaluationstandard. The results were shown in table 3.

TABLE 3 The surface appearance of the cellular molded article of thesynthetic resin having surface skin Example 12 ◯ Example 13 ◯ Example 14◯ Example 15 ◯ Example 16 ◯ Example 17 ◯ Comparative example 7 XComparative example 8 X Comparative example 9 X Comparative example 10 X

POTENTIAL FOR INDUSTRIAL APPLICATION

Method for producing cellular molded article in mold pattern ofsynthetic resin having surface skin and mold pattern producing thereofof this invention are suitable for use as a method for producingautomobile interior material or the like and mold pattern producingthereof, especially suitable for use to produce automobile interiormaterial or the like which has good production efficiency and comprisesof cellular molded article of synthetic resin obtained by cellularmolding of expanded beads in which poor melt bonding does not occur andthermoplastic resin skin material united with this cellular moldedarticle of synthetic resin which has excellent appearance withoutresiding beads pattern on its surface.

What is claimed is:
 1. A method for producing a cellular molded articleof a synthetic resin having a surface skin which comprises that in amethod for producing the cellular molded article of a synthetic resinhaving a surface skin in which thermoplastic resin skin material formedin this molding chamber is set in any one of two mold parts whichcomprises the molding chamber and after clamping the parts, expandedbeads are charged into this molding chamber, then expanded and meltbonded together by steam heating, along with being melt bonded andunited with the said thermoplastic resin skin material, at least thepart of the said one mold part on which the said thermoplastic resinskin material is set is made of gas permeable metal mold, gas permeableceramic mold or gas permeable electron casted mold having fine gaspermeable holes of not more than 100 μm of diameter on the whole surfaceand the said one part is made to be the upper mold part and the otherpart is made to be the lower mold part at least during the said steamheating and before expanding the said expanded beads.
 2. A method forproducing a cellular molded article of a synthetic resin having asurface skin which comprises that in a method for producing the cellularmolded article of the synthetic resin having a surface skin in whichthermoplastic resin is set in any one of two mold parts which comprisesthe molding chamber, and after clamping the parts, expanded beads arecharged into this molding chamber and then expanded and melt bondedtogether by steam heating, along with being melt bonded and united withthe said thermoplastic resin skin material, a fine unevenness having 5to 150 μm of amplitude, 30 to 600 μm of wavelength of the surfaceroughness waveshape is formed in advance on the surface of the said onemold part, and when melt bonding the said expanded beads together alongwith melt bonding and uniting these expanded beads with the saidthermoplastic resin skin material, by printing the said fine unevennesssurface to make the surface roughness of a prescribed range of thethermoplastic resin skin material and by the expanding force of the saidexpanded beads to press hard the thermoplastic resin skin material ontoone of the mold parts, the surface roughness of a prescribed range ofthe thermoplastic resin skin is made to be approximately the samesurface roughness of the other range, and the surface roughness of thisthermoplastic resin surface skin material is kept nearly uniform.
 3. Amethod for producing a cellular molded article of a synthetic resinhaving a surface skin which comprises that in a method for producing thecellular molded article of the synthetic resin having a surface skin inwhich a thermoplastic resin skin material is set in any one of two moldparts which comprises the molding chamber, and after clamping them,expanded beads are charged into this molding chamber, then expanded andmelt bonded together by steam heating, along with being melt and unitedwith the said thermoplastic resin skin material, an uneven printing itemmaterial is attached to the surface of one of the said mold parts inadvance, and when melt bonding the said expanded beads together alongwith melt bonding and uniting these expanded beads with the saidthermoplastic resin skin material are carried out, by printing a fineunevenness having 5 to 150 μm of amplitude, 30 to 600 μm of wavelengthof the surface roughness waveshape which is formed on the surface of thesaid uneven printing item material to make the surface roughness of aprescribed range of the thermoplastic resin skin material, which ispressed harder to the surface of the uneven printing item material withan expanding force of the said expanded beads, and the surface roughnessof the other range is to be approximately the same on the surface of thethermoplastic resin skin material, the surface roughness of thisthermoplastic resin skin material is nearly kept in a constant level. 4.A method for producing a cellular molded article of a synthetic resinhaving a surface skin which comprises that in a method for producing thecellular molded article of the synthetic resin having a surface skin inwhich cellular molded article of the synthetic resin and a thermoplasticresin skin material are set between two mold parts and when clamping theparts and pressurizing them, these cellular molded article of thesynthetic resin and thermoplastic resin skin material are united by heatand/or an adhesive, a fine unevenness having 5 to 150 μm of amplitude,30 to 600 μm of wavelength of the surface roughness waveshape is formedin advance on the surface of the one mold part which will come incontact with the said thermoplastic resin skin material, and whenuniting the said cellular molded article of the synthetic resin with thethermoplastic resin skin material is carried out, by printing the saidfine unevenness onto the surface of this thermoplastic resin skinmaterial, the prescribed range of surface roughness of the thermoplasticresin skin material which is pressed harder by the pressurizing force ismade to be approximately the same surface roughness to the other range,and the surface roughness of this thermoplastic resin skin material isnearly kept in a constant level.
 5. A method for producing a cellularmolded article of a synthetic resin having a surface skin whichcomprises that in a method for the producing cellular molded article ofthe synthetic resin having a surface skin in which the cellular moldedarticle of the synthetic resin and a thermoplastic resin skin materialare set between two mold parts, and when clamping the parts andpressurizing them, these cellular molded article of the synthetic resinand the thermoplastic resin skin material are united by heat and/or anadhesive, an uneven printing item material is attached in advance on thesurface of the one mold part which will come in contact with the saidthermoplastic resin skin material, and when uniting the said cellularmolded article of the synthetic resin with the thermoplastic resin skinmaterial, by printing fine unevenness having 5 to 150 μm of amplitude,30 to 600 μm of wavelength of the surface roughness waveshape which isformed on the surface of the said uneven printing item material to makethe surface roughness of a prescribed range of the thermoplastic resinskin material which is pressed harder to the surface of the said unevenprinting item material with a pressurizing force, and at a time ofuniting the said synthetic resin cellular molded article with thethermoplastic resin skin material, simultaneously by printing the fineunevenness having 5 to 150 μm of amplitude, 30 to 600 μm of wavelength,which are mounted on the surface of the said uneven item material forprinting, onto the surface of this thermoplastic resin skin material,and by means that a prescribed surface roughness of the thermoplasticresin skin material which is pressed harder to the surface of the saiduneven item material for printing by the pressurized force, theresulting surface roughness is made to be approximately the same to theother range, and thus the surface roughness of this thermoplastic resinsurface skin material is nearly kept in a constant level.
 6. A methodfor producing a cellular molded article of a synthetic resin having asurface skin which comprises that in a method for producing the cellularmolded article of the synthetic resin having a surface skin in which athermoplastic resin skin material is set in any one of two mold partswhich comprises the molding chamber, after clamping the parts, expandedbeads are charged into this molding chamber, and then expanded and meltbonded together by steam heating, along with being melt bonded andunited these expanded beads with the said thermoplastic resin skinmaterial, a fine unevenness whose difference from the said thermoplasticresin skin material is not more than 50 μm of amplitude, not more than200 μm of wavelength of the surface roughness waveshape is formed inadvance on the surface of the said one mold part, and when melt bondingthese expanded beads together along with melt bonding and uniting theseexpanded beads with the said thermoplastic resin skin material, byprinting the said fine unevenness to make the surface roughness of aprescribed range of the thermoplastic resin skin material which ispressed harder to the surface of the one mold part with an expandingforce of the said expanded beads and the surface roughness of the otherrange to be approximately the same on the surface of the thermoplasticresin skin material, the surface roughness of this thermoplastic resinskin material is nearly kept in a constant level.
 7. A method forproducing a cellular molded article of a synthetic resin having asurface skin which comprises that in a method for producing the cellularmolded article of the synthetic resin having a surface skin in which thecellular molded article of the synthetic resin and a thermoplastic resinskin material are set between two mold parts, and when clamping theparts and pressurizing them, these cellular molded article of thesynthetic resin and the thermoplastic resin skin material are united byheat and/or an adhesive, a fine unevenness whose difference from thesaid thermoplastic resin skin material is not more than 50 μm ofamplitude and not more than 200 μm of wavelength of the surfaceroughness waveshape is formed in advance on the surface of the one moldpart which will come in contact with the said thermoplastic resin skinmaterial, and when uniting the said cellular molded article of thesynthetic resin with the thermoplastic resin skin material, by printingthe said fine unevenness to make the surface roughness of a prescribedrange of the thermoplastic resin skin material which is pressed harderto the surface of the said one mold part with a pressurizing force andthe surface roughness of the other range to be approximately the same onthe surface of the thermoplastic resin skin material, the surfaceroughness of this thermoplastic resin skin material is nearly kept in aconstant level.
 8. A method for producing a cellular molded article of asynthetic resin having a surface skin of claim 3 or 5 wherein inaddition to the said fine unevenness, an unevenness for the productdesign pattern is formed in advance on the surface of the saidunevenness printing item material and when printing the said fineunevenness on the surface of the said thermoplastic resin skin material,the said unevenness for product design pattern is also printed.
 9. Amethod for producing a cellular molded article of a synthetic resinhaving a surface skin of claim 2, 4, 6 or 7 wherein the unevenness forproduct design pattern in addition to the said fine unevenness is formedin advance on the surface of the said one mold part, and the saidunevenness for product design pattern as well as the said fineunevenness is printed on the surface of the said thermoplastic resinskin material.
 10. A method for producing a cellular molded article of asynthetic resin having a surface skin of claim 2, 3, 4, 5, 6 or 7wherein the unevenness for product design pattern is formed in advanceon the surface of the said thermoplastic resin skin material beforesetting the thermoplastic resin material.
 11. A mold used for producinga cellular molded article of a synthetic resin having a surface skinwhich comprises that in a mold used for producing the cellular moldedarticle of the synthetic resin having a surface skin by a method inwhich a thermoplastic resin skin material is set in any one of two moldparts which comprises the molding chamber, and after clamping the parts,expanded beads are charged in this molding chamber, then expanded andmelt bonded together by steam heating, along with being melt bonded andunited with the said thermoplastic resin skin material, fine unevennesshaving 5 to 150 μm of amplitude, 30 to 600 μm of wavelength of thesurface roughness waveshape is formed on the surface of printing itemmaterial for making the unevenness which is attached on one mold part,or the said unevenness is formed on the surface of the said one moldpart by adhering the printing particles for making the unevenness onthis surface.
 12. A mold used for producing a cellular molded article ofa synthetic resin having a surface skin which comprises that in a moldfor producing the cellular molded article of the synthetic resin havinga surface skin by a method in which the cellular molded article of thesynthetic resin and a thermoplastic resin skin material are set betweentwo mold parts, and when clamping the parts and pressurizing them, thesecellular molded article of the synthetic resin and the thermoplasticresin skin material are united by heat and/or an adhesive, fineunevenness having 5 to 150 μm of amplitude, 30 to 600 μm of wavelengthis formed on the surface of printing item material for making theunevenness which is attached on one mold part to come in contact withthe thermoplastic resin skin material, or the said unevenness is formedon the surface of the said one mold part by adhering the printingparticles for making the unevenness on this surface.
 13. A mold used forproducing a cellular molded article of a synthetic resin having asurface skin which comprises that in a mold used for producing thecellular molded article of the synthetic resin having a surface skin bya method in which a thermoplastic resin skin material is set in any oneof two mold parts which comprises the molding chamber, and afterclamping the parts, expanded beads are charged into this moldingchamber, then expanded and melt bonded together by steam heating, alongwith being melt bonded and united with the said thermoplastic resin skinmaterial, fine unevenness whose difference from the said thermoplasticresin skin material is not more than 50 μm of amplitude and not morethan 200 μm of wavelength of the surface roughness waveshape is formedon the surface of printing item material for making the unevenness whichis attached on one mold part, or the said unevenness is formed on thesurface of the said one mold part by adhering the printing particles formaking the unevenness on this surface.
 14. A mold used for producing acellular molded article of a synthetic resin having a surface skin whichcomprises that in a mold for producing the cellular molded article ofthe synthetic resin having a surface skin by a method in which thecellular molded article of the synthetic resin and a thermoplastic resinskin material are set between two mold parts, and when clamping theparts and pressurizing them, these cellular molded article of thesynthetic resin and the thermoplastic resin skin material are united byheat and/or an adhesive, fine unevenness whose difference from the saidthermoplastic resin skin material is not more than 50 μm of amplitudeand not more than 200 μm of wavelength of the surface roughnesswaveshape is formed in advance on the surface of printing item materialfor making the unevenness which is attached on one mold part to come incontact with the said thermoplastic resin skin material, or the saidunevenness is formed on the surface of the said one mold part byadhering the printing particles for making the unevenness on thissurface.
 15. A mold used for prducing a cellular molded article of asynthetic resin of any of claim 11, 12, 13 or 14 wherein an unevennessfor product design pattern in addition to the said fine unevenness isformed.